Under “Keys and Access Tokens” you will find the Consumer Key and Consumer Secret which has to be entered in the Control Center, under Tools > White Label Settings > Twitter API Key and API Secret

Request a User’s Email Address

Requesting a user’s email address requires your application to be whitelisted by Twitter. To request access, please use this form.

Once whitelisted, the “Request email addresses from users” checkbox will be available under your app permissions on apps.twitter.com. Privacy Policy URL and Terms of Service URL fields will also be available under settings which are required for email access.